A number of components on-board an aircraft require electrical power for their activation. Many of these components are separate from the electrical components that are actually required to run the aircraft (i.e., the navigation system, fuel gauges, flight controls, and hydraulic systems). For example, aircraft also have catering equipment, heating/cooling systems, lavatories, power seats, water heaters, wing heaters, fuel warmers, and other components that require power as well. Specific components that may require external power include, but are not limited to, trash compactors (in galley and/or lavatory), ovens and warming compartments (e.g., steam ovens, convection ovens, bun warmers), optional dish washer, freezer, refrigerator, coffee and espresso makers, water heaters (for tea), air chillers and chilled compartments, galley waste disposal, heated or cooled bar carts/trolleys, surface cleaning, area heaters, cabin ventilation, independent ventilation, area or spot lights (e.g., cabin lights and/or reading lights for passenger seats), water supply, water line heating to prevent freezing, charging stations for passenger electronics, electrical sockets, vacuum generators, vacuum toilet assemblies, grey water interface valves, power seats (e.g., especially for business or first class seats), passenger entertainment units, emergency lighting, wing heaters for ice protection, fuel warmers, and combinations thereof. These components are important for passenger comfort and satisfaction, and many components are absolute necessities.
The relatively new technology of fuel cells provides a promising cleaner and quieter means to supplement energy sources already aboard aircrafts. A fuel cell has several outputs in addition to electrical power, and these other outputs often are not utilized. Fuel cell systems combine a fuel source of hydrogen (such as compressed hydrogen) with oxygen (such as oxygen contained in the air or oxygen provided by one or more oxygen generators) in order to produce electrical and thermal power as a main product. Water and oxygen depleted air (“ODA”) are produced as by-products, which are far less harmful than CO2 emissions from current aircraft power generation processes.
Additionally, aerospace vehicles and aircraft are also typically equipped with a fuel tank inerting system, which requires aircraft manufacturers to minimize flammability in fuel tanks to significantly reduce the risk of explosion. By way of background, a combination of warm fuel vapor and air in a fuel tank may be ignited by a low energy spark, and is known to be a cause of aircraft crashes. The inerting system decreases the oxygen levels of the air inside the fuel tanks. The inerting system produces inert gas, such as nitrogen enriched air, by means of an air separation module (ASM) that breaks down air into streams that are concentrated with individual components (i.e., oxygen, nitrogen, etc.). These inerting systems are typically referred to as on board inert gas generation system (“OBIGGS”) or fuel tank inerting system (“FTIS”).
In many cases, the supply of inlet gas to the inerting system is extracted from cabin air or from hot pressurized air output from the engine combustion chambers (bleed air). In both cases, inlet air has to be conditioned in pressure and temperature to ensure optimum performance of the OBIGGS and the inert gas distribution into tanks. When pumped by the engine compressor (i.e., bleed air inlet), the inlet air consumption decreases engine efficiency, thereby increasing fuel consumption. When pumped by a dedicated electrical compressor (i.e., cabin air inlet), this inlet air consumption also increases power consumption by increasing the power demand on the electrical compressor. These described systems also require power to be delivered directly or indirectly from the engines, which also translates into extra fuel consumption.
In addition to on-board gas tanks and cargo bay areas, electrical components aboard the aircraft may also pose a risk of fire even though such components are typically well isolated from exposure to combustible fuel vapors. This risk, however, is generally considered low enough that such electrical components are not subjected to the same scrutiny under safety regulations as fuel tanks, cargo bays, and other locations where fuel vapors may be expected to accumulate. A risk of fire may also exist on-board an aircraft in other compartments. There exists a risk exists that electrical components or other compartment areas may be subjected to excessive voltage, excessive current, or other conditions that may result in electric arc discharges, overheating of components, and/or other possible causes of fire ignition. Accordingly, new ways for adding or supplementing safety measures against fire risk for electrical components on-board aircraft may be desirable.